In some circumstances it may be necessary to restrain a switch from being turned on or off. For example, rules promulgated by the Occupational Safety and Health Administration (OHSA) require an electrical circuit breaker to be “locked-out,” i.e., restrained from being switched from an off position to an on position, for safety purposes to allow an individual to repair or install electrical equipment powered via the circuit breaker.
Manufacturers of electrical circuit breakers have developed a variety of devices for restraining individual circuit breaker switches. One such device disclosed in U.S. Pat. No. 4,347,412 is illustrated herein in FIG. 1. An inclined groove 52 extends into a surface 54 of the restraint device 50 at an angle 56 and accommodates a switch handle 58. When the restraint device 50 is mounted on the switch handle 58 the inclined groove 52 engages the switch handle 58 and the surface 54 engages a surface 60 of a switch housing 62, thereby inhibiting the switch handle 58 from moving relative to the switch housing 62.
Manufacturers may design the housing and switch handle of a circuit breaker switch such that only their respective restraint devices can interface therewith. For example, the housing may have a lip, groove, or ridge at a fixed distance from the switch handle such that the manufacturer's restraint device may be compatible with the circuit breaker switch, but restraint devices produced by competing manufacturers may not. A risk exists that an individual may place an incompatible restraint device on a circuit breaker resulting in failure of the restraint device and potential injury to the individual. Another problem with available switch restraint devices is their bulkiness. U.S. Pat. Nos. 5,079,390 and 5,147,991 each disclose a circuit breaker restraint device having a member whose width is equal to that of a switch handle. The large size of these restraint devices requires a significant amount of material and raises the cost of the restraint device. Moreover, the size of such devices may impede the ability of a user to close the outer door to the circuit breaker box. A need, therefore, exists for a universal switch restraint device that can be used without modification with a multiplicity of brands of circuit breakers.